Process for reducing fiber-yielding materials.



'G; H. MARSHALL;

PROCESS FOR REDUCING FIBBB-YIBLDING MATERIALS.

APPLIOATION FILED JUNE 10, 1909.

919% v Pamntems ph 27,1910.

GEORGE H. MARSHALL, F ROANOKE RAPIDS, NORTH CAROLINA.

Specification of Letters Patent.

Patented Sept 2t, 1910.

Application filed .Tune 10, 1909. Serial No. 501,380.

To all whom it may concern:

Be it known that I, GEORGE H. MARSHALL, a citizen of the United States, residing at Roanoke Rapids, in the county of Halifax and State of North Carolina, have invented certain new and useful Improvements in Processes for Reducing Fiber-Yielding Materials, of which the following is a specification, reference being had to the accompanyin'g drawings.

This invention relates to the treatment of fiber yielding materials of the cellulose variety, such as sugar cane, bagasse, cornstalks, sorghum, flax straw, etc. Large quantities of these materials are to be obtained as refuse matter in regions remote from centers where manufacturers might use them for various purposes, such as the manufacture of paper pulp andpaper, as well as for textile uses. Owing to the remoteness of the origin of such materials, the matter of transportation makes their cost in many cases prohibitive for the manufacturer. These materials containing cellulose fibers are in many cases destroyed by fire or other methods, and are a source of ex ense and trouble to the producers, the p ants being usually grown for other purposes, such for instance, as sugar cane which is grown for its sugar and flax which is grown for its seed, so that the stalks, as refuse matter, are a total lossto the farmer, it. is obvious that it is nearly always impracticable to manufacture these waste materials into commercial products at their points of origin owing to their remoteness from markets and the difficulty 'of securing skilled labor to utilize such waste materials. It will be quite apparent that if the useless contents of such materials can be removed by a simple cheap process, and the waste materials reduced 1n Weight, say fifty per cent, that it will be possible to make a large saving in freights and thereby place these materials at the disposal of many possible users, both producer and consumer be-,

ing thus materially benefited and an economy in natures products promoted This will be particularly true in the paper and pulp in-- dustries, as at the present moment the greatest source of raw'materials in these industries is wood of various kinds, the obtention l 12, which may of which is leading to the rapid depletion of the forests. a

It is the object of this invention to provide a simple and cheap process for such utilization of these products, which process consists intreating such waste or raw materials to a high steam pressure in a closed vessel preferably of a rotating type, inthe presence of a minimum amount of water and some neutralizing material of an alkaline nature, whereby the sugars, gums and useless dissolved and rendered'possible of removal by blowing the liquor from the closed vessel and afterward subjecting the treated material to washing and drying.

My improved process may be carried out by machinery of various forms and in order that the process may be readily carried tratod a preferred form in the accompanying drawing in which-'- F'gure 1 is a diagrammatic illustration, with some of the parts shown in section and some broken away, and Fig. 2 is an elevation of the rotary boiler looking at the right hand thereof as'shown in Fig. 1.

Referring specifically to the drawing, 1 indicates aclosed vessel or boiler of a well known elongated rotary type, 2, 2, the trunwhich transrotate, and 3, 4, 5, 6 the gearin e rotation of units the necessary power for t the boiler. l

The boiler is rovided at one-end with a discharge spout in which is located a valve 8 of any suitable form to permit of the blowing out of its liquid contents, a swing pipe 9 being connected with the end of the spout, through which'the liquld contents, with the steam used for blowing, and any accumulated gases, maybe passed and conveved to any desired point.

Connected with one of the trunn1ons 2, which is itself hollow, is a steam inlet pipe 10, the entrance of steam into the boiler being controlled by a suitable valve-11 1n said pipe.

The boiler is provided at the end opposlte the discharge s out 7 with a suitable cover lie hinged for convenience of incrusting matters are disintegrated and out by those skilled in the art, I have illusnions upon which the boiler is mounted to together operation, which cover is rendered hermetically tight by being screwed down by bolts 13 upon a suitable gasket 14. Within the boiler 1, near the discharge end, is a transverse screen 15.

Above and slightly to one side of the boiler is a suitable tank 16 in which the solution to be used in the boiler is mixed, and

leading from the bottom of said tank is a' pipe 17 having a suitable valve 18, a swing pipe 19 being attached to the end of said pipe 17 in such position that when the pipe 19 is swung down, as shown in dotted lines, the contents of the tank 16 may be discharged into the boiler. Also above and to one side of the boiler is a conveyer of any preferred form, being here shown as an endless belt 20 mounted on pulleys 21, the said conveyor leading to the boiler in order to convey the materials to be treated thereto.

Below the boiler is located a suitable conveyer, here shown as an endless belt 22, on pulleys 23, which serves to convey solid contents discharged from the boiler as here-- inatter described, to squeeze rolls 2 1, and above said rolls, is a water pipe 25 suitably perforated, to discharge water on the matter entering between the rolls. Below the rolls 24 is another conveyer, shown as an endless belt 26 on pulleys 27, which lead to another set of squeeze rolls 98, below which is another conveyer belt 28 mounted on suitable pulleys, as at 30 and leading into a dry house or kiln 31, one of the pulleys supporting belt 29 being within the dry house, which may be heated in any suitable manner, and suitable idler rollers 32 being provided to support the conveyer belt 29 owing to its length.

The raw materials are brought to the rotating boiler by the conveyer 20, and discharged into the boiler, the boiler being in a vertical position, with the lid 12 at the top and open.

The ncutralizii'ig solution being mixed in the tank 16, the swing pipe 19 is lowered into the opening of the boiler and the contents of the tank allowed to flow into the boiler.

The neutralizing solution is composed of water with which may be mixed chalk, powdered limestone, lime, or any material of a weak alkaline nature.

A minimum amount of water should be added to the material under treatment in the boiler, and to this end, if the materials are wet, the amount should be approximately a weight of water equal to the weight of the material, and if the material under treatment is quite dry, then there should be a weight of water twice to three times the weight of the material in the boiler.

If the material to be treated is green or very wet, very little water need be added,

in fact less than an equal weight of the water as above stated, because to effectively carry out my process a minimum amount of water must be used, and the steam that condenses supplies some water. 1 have found that the use of a minimum amount of water or solution together with the heat and direct cont-act of the steam, and also a suiiieient amount of neutralizing alkaline substance enables me to effectively remove sugar, gums and glutinous matters without injuring the fiber proper and the lignin or ligneous inerusting matters which I desire to leave partially if not wholly intact. It is in this particular that my process difiers with others heretofore used. The use of a minimum amount of water or solution in the material necessitates the expenditure of a minimum amount of fuel which is required to produce the heat which performs the reduction. The. use of a minimum amount of solution-not only enables my to be carried out. on the basis of extreme economy in respect to the cost of fuel, but it also exposes the material under treatmmit to a greater oti'cctive steam area.

The alkaline contents should be from three to ten per cent. of the weight of material under treatment, the variation of the character of the materials under treatment making it necessary to vary the amountof the neutralizing substances.

By the foregoing statement, namely, that the alkaline contained should be from three to ten per cent. of the weight of the material nnder treatment 1 mean the weight of the material when wetor saturated with water; and while these are preferably the proportions used a smaller amount of the alkaline neutralizing substance may be used in the treatment of similar materials.

The materials under treatment, and the neutralizing solution, having been placed in the boiler the cover 12 is then put on and securely bolted to make a tight joint. Steam is then slowly admitted to the boiler through pipelO and valve 11 and the boiler rotated on the trunnions by the gearing 3 at a speed of preferably one revolution in two minutes. The steam is allowed to flow into the boiler for say about fifteen minutes when it is cut off and the boiler stopped with the valve 8 at the top, being in a vertical position. The valve 8 is now opened sutliciently to allow the heated air to escape when it is again closed tight-1y, the boiler again set in motion, and the steam again turned on, the pressure being allowed to rise slowly to about 150 pounds, where it is kept for from one to three hours according to the condition of the material under treatment, green material requiring a short time and old and dry material a much longer period.

The loaded boiler having been kept rotating and under the steam pressure for from one to three hours, the material within it will have all the gums and useless matter softened sufiiciently to permit of blowing down the pressure The boiler therefore at this period, is stopped in a vertical position, with the valve 8 at the lower end and connection is made to the pipe 9. The valve 8 is now openedas quickly as possible and the resultant liquors in the boiler blown out through the screen 15 which prevents the passage of the material into the pipe 9. The blowing down of the pressure in as short a time as safety will permit, accomplishes a double purpose; first, the quick release of pressure tends to explode the piths or woody portions of the materials in the boiler, such as the pith in sugar cane and the woody boon or stalk in fiax straw, and allows this disintegrated matter to pass out more or less with the quick rush of steam through the blow out valve 8. The resultantliquors having been blown out, and the steam pressure having been reduced to atmospheric pressure, the cover 12 is then removed and the boiler turned so that the contents will fall upon the conveyer 22 and be conducted to the squeeze rolls 2 where it receives a shower of water from pipe 25 which washes out the dirt and waste products which failed to pass oil? in the blow off operation. From the rolls 24 the material passes to another conveyer 26 and thence to a second set of squeeze rolls 28 which remove the surplus water and the material thence passes on the conveyer 29 through the dry house or kiln 31 which may be of any desired or suitable type.

If preferred, the finished product may be dried in the open air and then baled for shipment.

By the foregoing process I do not claim to make a complete or pure finished cellulose product, but I make an average reduction in the wei ht of the materials of fully fifty per cent, w ich enables the farmer to profitably ship such partiall reduced product to the manufacturer, suc' partially reduced material, or half pulp being capable of being further profitably reduced in manufacturing plants suitably equipped for handling such materials;

It will be noted that my process is only a partial reduction process and must be carried out on the basis of extreme economy in order to be practical. It is therefore important that a minimum amount of water or solution be used so that the cost of fuel will be reduced to a minimum and a minimum amount of neutralizing substance will be necessary. If a-large amount of solution is used as in other processes now used,.the cost of fuel would exceed the cost of raw material under treatment. Furthermore, when large quantities of solutions and chemicals are used in carrying out the old process very drastic treatment ensues and the result is the injury to or total separation of the fiber and its ligneous incru'sting matter.

Having thus fully described my invention,

what. I claim as new and desire to secure by Letters Patent, is-

1. The herein described process of treating fiber yielding materials which consists in introducing the materials in a digestertoget-her with an alkaline neutralizing agent and a minimum amount of water or moisture, which amount is sutlicient to thoroughly saturate the materials and agent, then subjecting the contents of the digester to a mild steam pressure while rotating the digester, then exhausting air and gases from together with an alkaline solution, then subjecting the materials to a mild steam pressure while rotating them, then exhausting the air and gases from the digester, then gradually increasing the steam pressure Within the digester while the materials are. being rotated, then suddenly reducing the pressure and blowing ofi' the liquids from the digester, then removing the fibrous materials from the digester, and then successively washin the fibrous materials and squeezing the moisture therefrom.

3. The herein described process of treating fiber yielding materials which consists in introducing the materials in a digester, to-

ether with an alkaline solution, then subecting the materials to a mild steam pressure while rotating them, then exhausting the air and gases from the digester, then gradually increasing the steam pressure within the digester while the materials are being rotated, then suddenly reducing the pressure and blowing oil the uids from the digester, then removin the throne materials from the digester, teen spraying the fibrous materials with water and squeezing them to remove the moisture, then subject-- ing the fibrous materials to a second squeezing action, and then drying the fibrous materials.

4. The herein described process of treating fiber yielding materials, which consists in introducing the materials in a digester, to ether with an alkaline solution, then. sufijecting the materials, to a mild steam pressure While rotating them, then exhausting the air and gases from the digester, then gradually increasing the steam pressure within the digester While the materials are being rotated, then suddenly reducing the pressure and blowing off the liquids from the digester, then removing the fibrous materials from the digester, then spraying the fibrous materials with Water and squeezing 10 them to remove the moisture, then subjecting the fibrous materials to a second squeezing action, then drying the fibrous material and finally packing the latter for shipment.

In testimony whereof I hereunto aflix my signature in the presence of two witnesses. 1.5

GEO. H. MARSHALL.

Witnesses:

H. MURPHY, J. T. CHASE. 

